Amplifier matrixes such as the well-known Fourier transform matrix (FTM) have been used in cellular base stations for quite some time. An illustration of a Fourier transform matrix used to evenly distribute power amongst three amplifiers is provided in FIG. 1. Typically, a Fourier transform matrix has an input matrix portion, an output matrix portion, amplifiers coupled therebetween, and antennas coupled to the outputs of the output matrix.
When FTMs are paired to transmit to different sectors in a cellular system, optimal signal quality and isolation between sectors will be attained if each of the transmit paths has the same gain and phase. Such a system is said to have a high degree of sector-to-sector isolation (SSI). Imbalances between transmit paths in either gain or phase will degrade SSI resulting in decreased transmission quality and, in some systems, decreased data transmission rates.
What is needed is a system and method for helping to maximize SSI so that imbalances between transmit paths are minimized while transmission quality and transmission rates are not degraded.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.